Pierce anti myc magnetic beads

Five million cells were used for the ChIP assay of each target. Cells were washed with PBS, crosslinked with 1% formaldehyde for 5 min at room temperature, and then quenched with 125-mM glycine for 5 min. Wash cells twice with ice-cold PBS. The isolated nuclei were resuspended in 250-µl nuclei lysis/sonication buffer and sonicated with XINCHEN VXV130 sonicator with the following parameters: duty cycle 22% and time: 20 s on and 20 s off for 9–12 cycles. After centrifugation at 4° with 13,500 rpm for 10 min, soluble chromatin was used to perform immunoprecipitation, while 5% of the sample was kept as input DNA. Immunoprecipitation was performed with 5 ~ 10 μg indicated Pierce Anti-MYC Magnetic Beads (Thermo Scientific, 88,842), H3K4me3 (PTM BIO, PTM613), or IgG (Abclonal, AC011) overnight at 4° with rotation and then washed sequentially using low salt, high salt, LiCl buffer, and TE buffer. Bound DNA was then eluted, reverse-crosslinked, and incubated with RNase A and proteinase K. DNA samples were purified using a Universal DNA Purification Kit (Tiangen, DP214-02). Primers for ChIP-qPCR analysis were listed in Additional file 8: Table S7.